[mythtv-users] Record Multiple Channels on a Single Multiplex(using getstream)?

[Brad Templeton]

On Wed, Jun 28, 2006 at 04:32:43PM -0400, Boleslaw Ciesielski wrote:
> Brad Templeton wrote:
> > If you could get a cable company with unencrypted QAM, that would be
> > a different story, since there will be 8 or more unrelated SDTV channels
> > on a single QAM channel, though again it will be the boring digital TV
> > channels, not something so nice as ABC, CBS and NBC on the same frequency.
> 
> Where I live (Boston area) Comcast is transmitting almost all broadcast 
> HD channels (ABC, CBS, NBC, FOX, WB, PBS) unencrypted two per multiplex:
> 
> 
> and UPN-HD is bundled with the other 3 PBS (SD) channels:
> 
> And all major SD channels are on a single multiplex:
> 
> So 5 multiplexes cover pretty much anything useful that you can get from 
> unencrypted QAM.

I take it back then, this does seem like a useful thing to
support, even more in the UK.    I mean in a way it makes sense
if stations would cooperate like this in the OTA field, cheaper to
rent half of somebody else's bandwidth than to have your own transmitter.

However, since you can't really get two HD channels on a 19 megabit ATSC channel
with mpeg-2, that pretty much requires every HD channel to have their
own band and transmitter, so cooperation won't help that much.   SD channels
could group together, 4 to a transmitter or so, but who cares about SD
channels?   For the live tv watcher, it would at least allow instantaneous
channel change (with some cleverness and slight buffering) again.   The
rare times I do delve into live TV these days, one thing I miss is the old
instant channel change of analog.

Instant channel change could be possible with multiple tuners and some
predictive recording.   You could have tuners tune the "next" likely
channel, and note the presence of key-frames, and if you really do tune to
that channel, instantly give you signal from that most recent key frame
(or with more CPU the true current frame) but that's a lot of work for
something minor.